1. Field of the Invention
The present invention relates to a method of self-assembling silicon quantum dots, and especially relates to the self-assembling silicon quantum dots on an amorphous silicon film by an excimer laser.
2. Description of Prior Art
In recent years, semiconductor quantum dots have been extensively applied in the field of photonics devices, such as photo-detectors, light emitting diodes (LEDs), semiconductor laser diodes (LDs), single electron devices, and others. A large number of experimental and theoretical studies have investigated semiconductor quantum dots.
Quantum dots are usually formed by using quantum well structure. U.S. Pat. No. 5,229,320 disclosed xe2x80x9cMethod For Forming Quantum Dotsxe2x80x9d. With reference to FIG. 1A to FIG. 1D, a film of quantum well formed on a substrate and then a layer 10 of photoresist formed thereon. Finally, the quantum dots 32 formed on a film of quantum well by the electron-beam lithography. However, the methods cause a lot of surface states, and the surface states became the main source of non-radiative recombination center. Further, the surface state reduced the optical property of quantum dots. For example, the intensity of luminance resulting from conventional quantum dots is lower than that resulting from quantum well. The optical linewidth caused by the conventional quantum dots is wider than that caused by the quantum well. In addition, the method of electron-beam lithography is slow and has difficulty manufacturing a large-area device.
Quantum dots can also be formed in the Stranski-Krastanov mode (SK mode) by MBE or MOCVD. However, the quantum dots formed by MBE or MOCVD are restricted to the material of InAs/GaAs or SiGe/Si, and confined to the substrate.
In accordance with the present invention, the object is attained by a method of self-assembling quantum dots. A thin Si film forms on a substrate and then the thin Si film ( less than 100 nm) is formed into poly-Si quantum dots by utilizing an excimer laser to proceed with the annealing process.
The present invention has an advantage in that the quantum dots of Si are simply and quickly formed by the self-assembling method. Further, utilizing a laser scanner on a large-area film of Si can form a large-area device of Si quantum dots.